Can at‐risk species serve as effective conservation surrogates? Case study in northeastern US shrublands

Abstract

Abstract Targeted, single‐species management and ecosystem‐based management are generally considered disparate conservation approaches. In imperiled ecosystems, these approaches may be complementary, when habitat management for targeted at‐risk species provides broad ecosystem benefits through an umbrella or surrogate species effect. In the northeastern United States, extensive management has been ongoing since 2011 to restore declining habitat for an at‐risk shrubland habitat specialist, the New England cottontail (Sylvilagus transitionalis), with the goal that other shrubland‐obligate wildlife will also benefit; yet, the efficacy of these efforts has not been evaluated. In this study, we assessed whether habitat management targeting New England cottontail provides conservation benefits for shrubland‐obligate birds. Specifically, we (1) identified shrubland‐obligate birds that are indicative of the microhabitat conditions and habitat types suitable for New England cottontails, and (2) determined microhabitat and patch‐level influences on shrubland bird occupancy at sites occupied by or managed for New England cottontail. Through avian point count surveys and indicator species analyses, we identified 12 shrubland‐obligate bird species on patches occupied by New England cottontail and in microhabitat conditions suitable for New England cottontail. Occupancy models for five shrubland bird species further identified species‐specific habitat associations. Generalized linear models showed that shrubland bird species richness was positively associated with herbaceous vegetation and low shrubs, indicating that shrublands managed for the purpose of cottontail colonization can also benefit a suite of shrubland birds before the habitat is dense enough to provide cover for cottontails. Our findings show that managing habitat for New England cottontail on a variety of site types can maintain a range of microhabitat conditions to support a high diversity of shrubland‐obligate birds. These findings provide evidence for broad ecosystem benefits of managing for New England cottontail and exemplify the value of at‐risk habitat specialists as conservation surrogates in imperiled ecosystems.

Keywords

• at‐risk species
• indicator species analysis
• occupancy model
• shrubland bird
• surrogate species
• Sylvilagus transitionalis